The Wonder of 0.7% (7/1000)

Recall that, when hydrogen is transformed into helium in the Sun,

0.7% (7/1000) of the hydrogen's mass
is converted into energy for each
helium nucleus formed

bulletSuppose that 0.7% were 0.6% instead ...

Then the bonding of hydrogen nuclei in the first step of the Sun's fusion chain would be too weak and unstable!

bottleneck.gif (1119 bytes)

The whole universe would consist of hydrogen atoms!
No stars ... no planets ... no other elements!

bullet

Suppose that 0.7% were 0.8% instead ...

Then the bonding of hydrogen nuclei in the Big Bang nucleosynthesis would been too strong!  All of the hydrogen would have been used up to form heavier nuclei!

There would be no hydrogen fuel to allow stars to burn, no water to support life!

Any universe with complex chemistry
requires the strength of the
nuclear bonding force
to be "just right,"
0.7%

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